Reduction of graphene oxide （GO） is a promising low-cost synthetic approach to bulk graphene, which offers an accessible route to transparent conducting films and flexible electronics. Unfortunately, the release of ...Reduction of graphene oxide （GO） is a promising low-cost synthetic approach to bulk graphene, which offers an accessible route to transparent conducting films and flexible electronics. Unfortunately, the release of oxygen-containing functional groups inevitably leaves behind vacancies and topological defects on the reduced GO sheet, and its low electrical conductivity hinders the development of practical applications. Here, we present a strategy for real-time repair of the newborn vacancies with carbon radicals produced by thermal decomposition of a suitable precursor. The sheet conductivity of thus-obtained single-layer graphene was raised more than six-fold to 350-410 S/cm （whilst retaining 〉96% transparency）. X-ray photoelectron spectroscopy （XPS） and Raman spectroscopy revealed that the conductivity enhancement can be attributed to the formation of additional sp2-C structures. This method provides a simple and efficient process for obtaining highly conductive transparent graphene films.展开更多
In this study, a simple spraying method is used to prepare the transparent conductive films （TCFs） based on Ag nanowires （AgNWs）. Polyvinylpyrrolidone （PVP） is introduced to modify the interface of substrate. Th...In this study, a simple spraying method is used to prepare the transparent conductive films （TCFs） based on Ag nanowires （AgNWs）. Polyvinylpyrrolidone （PVP） is introduced to modify the interface of substrate. The transmittance and bending performance are improved by optimizing the number of spraying times and the solution concentration and controlling the annealing time. The spraying times of 20, the concentration of 2 mg/mL and the annealing time of 10 min are chosen to fabricate the PVP/AgNWs films. The transmittance of PVP/AgNWs films is 53.4%----67.9% at 380---780 nm, and the sheet resistance is 30 f~/n which is equivalent to that of commercial indium tin oxide （1TO）. During cyclic bending tests to 500 cycles with bending radius of 5 ram, the changes of resistivity are negligible. The performance of PVP/AgNW transparent electrodes has little change after being exposed to the normal environment for 1 000 h. The adhesion to polymeric substrate and the ability to endure bending stress in AgNWs network films are both significantly improved by introducing PVP. Spraying method makes AgNWs form a stratified structure on large-area polymer substrates, and the vacuum annealing method is used to weld the AgNWs together at junctions and substrates, which can improve the electrical conductivity. The experimental results indicate that PVP/AgNW transpar- ent electrodes can be used as transparent conductive electrodes in flexible organic light emitting diodes （OLEDs）.展开更多
基金This work was supported by the National Natural Science Foundation of China （Grants Nos. 50802003, 20973013, 51072004, 50821061, and 20973006） and Ministry of Science and Technology of the people＇s Republic of China （Grants Nos. 2007CB936203, 2006CBP32602, and 2009CB929403）.
文摘Reduction of graphene oxide （GO） is a promising low-cost synthetic approach to bulk graphene, which offers an accessible route to transparent conducting films and flexible electronics. Unfortunately, the release of oxygen-containing functional groups inevitably leaves behind vacancies and topological defects on the reduced GO sheet, and its low electrical conductivity hinders the development of practical applications. Here, we present a strategy for real-time repair of the newborn vacancies with carbon radicals produced by thermal decomposition of a suitable precursor. The sheet conductivity of thus-obtained single-layer graphene was raised more than six-fold to 350-410 S/cm （whilst retaining 〉96% transparency）. X-ray photoelectron spectroscopy （XPS） and Raman spectroscopy revealed that the conductivity enhancement can be attributed to the formation of additional sp2-C structures. This method provides a simple and efficient process for obtaining highly conductive transparent graphene films.
基金supported by the National Natural Science Foundation of China(No.21174036)the National High Technology Research and Development Program of China(No.2012AA011901)the National Basic Research Program of China(No.2012CB723406)
文摘In this study, a simple spraying method is used to prepare the transparent conductive films （TCFs） based on Ag nanowires （AgNWs）. Polyvinylpyrrolidone （PVP） is introduced to modify the interface of substrate. The transmittance and bending performance are improved by optimizing the number of spraying times and the solution concentration and controlling the annealing time. The spraying times of 20, the concentration of 2 mg/mL and the annealing time of 10 min are chosen to fabricate the PVP/AgNWs films. The transmittance of PVP/AgNWs films is 53.4%----67.9% at 380---780 nm, and the sheet resistance is 30 f~/n which is equivalent to that of commercial indium tin oxide （1TO）. During cyclic bending tests to 500 cycles with bending radius of 5 ram, the changes of resistivity are negligible. The performance of PVP/AgNW transparent electrodes has little change after being exposed to the normal environment for 1 000 h. The adhesion to polymeric substrate and the ability to endure bending stress in AgNWs network films are both significantly improved by introducing PVP. Spraying method makes AgNWs form a stratified structure on large-area polymer substrates, and the vacuum annealing method is used to weld the AgNWs together at junctions and substrates, which can improve the electrical conductivity. The experimental results indicate that PVP/AgNW transpar- ent electrodes can be used as transparent conductive electrodes in flexible organic light emitting diodes （OLEDs）.
